Watch-escapement



C. E. DE LONG.

WATCH ESCAPEMENT.

APPLICATION FILED 1ULY13, 191s. RENEWED JUNE 12, 1919.

Patented Jan. 6, 1920.

2 SHEETS-SHEET I C. E. DE LONG.

WATCH ESCAPEMENT. APPLICATION FILED JULY as. 1916. RENEWED JUNE 12, 1919.

1,327,226, Patented Jan. 6, 1920.

2 SHEETSSHEET 2.

@331 1:4 attozme a 7 this requires the use of UNITED STTES PATENT OFFICE.

CHARLES E. DE LONG, OF NEW YORK, N. Y.

WATCH-ESCAPEMENT.

Specification of Letters Patent.

Continuation of application Serial No. 18.470, filed April 1, 1815. This application filed July 13, 1916,

Serial No. 109,042.

To aZZ whom it may concern Be it known that 1, CHARLES E. DE LONG, a citizen of the United States of America, and a resident the borough of Manhattan, city, county, and State of New York, have invented certain new and useful Improvements in "Watch-Escapements, of which the following is a specification.

Myinvention relates to an improvement in detached lever escapements for timepieces,

wherein the balance-wheel and hairspring act as governor and regulator of the intervals of escapement.

1n detached lever escapements for timepieces most generally in use at the present time, and which may be called standard escapements, rectangular ewel's having an active end face are introduced into slots in the lever commonly used, the slots being made by hand or by machinery as by sawing or slotting machines. The pallets must be fitted and thereafter held more or less precariously against displacement in the slot by cementation. in this form of escapement the highest ingenuity and skill of the lapidary and of the watchmaker must be eXe rised in the construction of the parts and in the assembling thereof. The palletsare positioned in the lever sothat they have different inclinations respectively to the center line of the lover. The slots in which they fit are openended, and, for reasons apparent to those skilled in the art, they cannot be made by a punching operation, but must be made by sawing or slotting. If they are sawed, any non-uniformity in the operation of the saw will produce a misplaced slot. The saws are likely to wear and change the dimensions of the slot and the location. The replacing of the saw necessitates a readjustment of the saw-operating means, which is likely to produce a variation in the completed lever. In manufacturing the standard type of lever, the opening for the staii must be drilled, and a drill jig. There must be freedom or play between the jig and the drill, and the tendency of small drills is to run to one side, and, therefore, since there movement of the drill relatively to the jig and the drill tends to deviate from its true path, it is impossible to secure accurate positioning of the staif opening. The pallets are rectangular in cross-section, and they each have an. active face formed at one end. The angle which the active face of the entrance pallet forms with the longitudinal Renewed June 12, 1919.

Serial No. 303,769.

axis thereof is diflerent from the angle formed between the active face of the exit pallet and the longitudinal axis of the exit pallet. It is, therefore, at once apparent that the jewels in the standard escapement are in no way interchangeable. The slots which the pallets fit are necessarily larger than the jewels, in order that cement of some character may be placed between the pallet and the walls of the slot. This freedom causes variations in the positioning of the pallets in difierent levers and relatively-t0 one another in the same lever, even though the pallets and levers are all identically constructed. In the standard escapement, in which there is so much possibility of and necessity for adjustment of the jewels, each escapement must be assembled with great care by a highly skilled artisan at the expense of much time, in order to secure any kind of uniformity of operation. Even though the parts of the lever are assembled with the aid of a mechanical device, in order to secure as much standardization as possible, it is necessary to change the adjustment of the parts in assembling the lever with the escapement wheel, because of the variations in the positioning of the staff relatively to the pallets and the variations in the relative positioning of the lever staff and escapement wheel shaft. Furthermore, when a watch which is not keeping accurate time is submitted to an unskilled watchmaker for adjustment, it is possible for him to change the adjustment of the pallets relatively to the lever, and, because of his lack of skill, the usual result is that the watch is made practically worthless until it can be taken to a skilled artisan for adjustment.

The various objects of my invention are to avoid, among others, the above-enumerated disadvantages and insufiiciencies of the socalled standard type of escapement. To this end, my escapement consists of a lever which is made by a punching operation, whereby thousands upon thousands of levers may be produced with absolute uniformity before a replacing of the punching device is necessary; and, further, in the hf cement; and, further, in the making of the pallets substantially identical; and, further, in the positioning of the pallets so that they extend at right angles to the plane of the escapement lever; and, further,

in the design of the pallets and escapement positioning of the pallets without the use wheel teeth, so that there are lifting faces on both; and, further, in designing my escapement so that there is equal lock and drop. Another very important advantage of my escapement lies in the fact that it is designed so that the resistance to unlocking decreases as the lever is moved toward the center position, which is brought about by designing the parts so that practically no retrograde movement of the train occurs as unlocking takes place, whereas in the so-called standard type there is an increasing resistance to unlocking right up to the point where the tooth slips over the corner of the pallet, because the unlocking movement of the lever causes a retrograde movement of the escapement wheel. In the form of escapement including polygonal pallets which is illustrated in the drawings of this application by way of example, the amount of draw upon the lever increases as the entrance pallet moves from looking to unlocking position so that there is an increasing resistance to unlocking so far as the entrance stone is concerned. As the exit stone, however, moves from locking to unlocking position, the amount of draw decreases so that the resistance to unlocking decreases as the exit stone moves from looking to unlocking position. This lack of uniformity gives rise to considerable possibility of error in the ordinary type of escapement. A constructional advantage derived lrom my form oi escapement is that the absence of the necessity for the use 01" cement for securing the pallets makes it possible to use considerably lighter stock for the lever and thereby greatly reduce the inertia forces of the moving parts, so that the lever as here disclosed is practically in poise without the use of counter-balancing parts. The great desirability of interchangeable parts, such as the pallets, is undisputed. y making the pallets interchangeable, the variation in the angularity of the lift or impulse face of the entrance and exit pallets may be taken care of by the angularity oi the positions of the recesses or openings in the lever in which the pallets are fixed. It may, however, be desirable to have the pallets different in size and contour, so that in assembling the parts the watchmaker may be assisted in determining which pallets shall be placed in the recesses or openings of the lever by the difference in contour, not only of the pallet, but also of the recess into which the pallet is to be fitted. In order to secure an operative escapcment, wherein the pallets are interchangeable, and wherein equal lock and drop are secured, particular proportions have been worked out by calculation and experiment, and they are herein set forth by dimensions on the drawings, certain ones of which are drawn to scale, in order that this invention may be fully set forth to enable those skilled in the art to practice the same.

This specificati n is a continuation of my copending application, Serial Number 1851-70, for improvements in watch escapements, filed April 1, 1915.

Further objects and advantages will appear from the following description, taken in connection with the drawings forming part of this specification, and will be pointed out .in the hereunto-appended claims.

In the drawings, in which like reference characters indicate similar parts,

Figure 1 is a drawing substantially to scale and including essential relations and dimensions of an escapeinent embodying he principal features of my invention;

Fig. 2 is a drawing substantially to scale and showing certain essential rela tions of a so-called standard escapement;

Fig. 3 is a side view or the escapement lever shown in Fig. 1;

Figs. 4, 5 and 6 are detail views, showing various cross-sectional shapes for pallets.

Referring to Fig. 1 of the drawings, the escapement wheel 1 may be of any wellknown club-toothed type. The escapement lever 2 car ies the pallets 3 and is pivoted at a. Fig. 1 is diagrammatic, and the roller jewel 5, carried by the roller of the balancewheel, is shown in proper relation to the horns 6 of the escapement wheel. The dart or guard 7 is also indicated. This guard or dart may be made in any well-known manner; for instance, by attaching a separate piece to the lever, or by forming a piece integral with the lever and offsetting it by a swaging operation. The lever is made by a stamping operation with dies,

and by dies which form. the outer peripheral contour of the lever and at the same time make the openings for the staff and for the jewels. In order to cut the pallet openings by punches, it is necessary that a small shoulder of material, shown in dotted lines indicated by the numeral 7, be left on the outer end of the lever arms. The pallet holes are cut by the punch together with the openings 8, which lead thereinto, and then the part 7 is ground oil, so that the opening 8 becomes an open-ended slot, as shown in solid lines in Fig. 1. The pallets are preferably jewels and may have a cross-section like those shown in Figs. 4, 5 and 6, or any crosssection which is the equivalent of those shown. It will be noted that each cross-section has a complete diameter AB, and that the face of the jewel forms a chord CD, which is parallel with and spaced to one side oi the diameter AB. lVhatever form of cross-section is chosen, the openings for the pallets in the lever should be made to correspond. It will be noted that the ends of the lever are bifurcated, so that branches 10 and 11 are formed. The branch 10, as will be seen, has a plane face, against which the plane active face of the jewel is positioned. The arm 10 is made thick, so as to be rigid, and, therefore, after the lever is punched out, the relation of the active faces of the pallets to the stafi' is absolutely fixed. The arm 11 is less rigid than the arm 10, and, if the jewel is slightly larger than the opening, the arm 11 may be sprung, and it will thereupon hold the jewel in the proper position above described.

The various relations of the parts are fully disclosed upon the drawings by dimensions and angles, and it has been found that particular relations are essential to the successful operation of my invention. It will be seen that a circle struck from the center of the staff opening and passing through the center of the eXit pallet will pass inside of the center of the entrance pallet. It will also be seen that a circle struck from the center of the lever staff and passing through the locking corner of the exit pallet will pass nowhere near the locking corner of the entrance pallet. The escapement is, therefor, neither a circular pallet type nor an equidistant locking type.

The pallets being held in place relatively to the lever by the clamping action of the branches or jaws of the bifurcated arms of the lever, no cement is necessary, and, therefore, very thin material may be used for the lever. The lessening of inertia tends toward uniformity of operation.

An advantage which is obtained from my particular arrangement of parts and which tends toward accuracy of time-keeping is that the lock on both the entrance and exit pallets is practically the same. The amount of locking is measured by the angle between radii drawn from the lever axis and passing respectively through the locking point of the tooth and the locking corner of the jewel. On the entrance pallet this is shown to be 1 55, and on the exit pallet it is shown to be 2. The drop, which is the free movement of the escape wheel tooth after it leaves a corner of the pallet, is shown to be 11;", and is the same with regard to each pallet. It is apparent that equal lock and drop tend to secure the greatest uniformity of operation, and it is only by my particular arrangement that .I am enabled to secure these advantages in connection with identically-shaped entrance and exit pallets.

The standard escapement shown in Fig. 2 has lifting faces on both the pallets and the escape wheel teeth. This is a highly desirable form of construction, and I have embodied it in my device. The total angular displacement of the lever 2 is secured or produced during the passage of a lifting face 110 of one of the escape wheel teeth across a lift ing face 111 of one of the jewels 8. Upon reference to Fig. 2, it is seen that the jewels in the standard escapement are positioned in open-ended slots, having different angles relatively to the center line of the lever. The entrance and exit pallets in this form of escapement are also different in shape from one another. Furthermore, the making of these pallets requires six independent manipulations by the lapidary; namely, the four sides must each be separately squared and trued, and the base of the pallet must be leveled off, and, finally, the most trying of all the manipulations, the formation of the lifting face at the proper angle must be made. Even after this elaborate jewel is formed and set within its appropriate slot, its positioning is a matter of adjustment by the most skilled of watchmakers, and after it is adjusted it is susceptible to movement which will destroy the accuracy of operation of the watch.

The jewels in my form of escapement may have any of the cross-sections shown in Figs. 4:, 5 and 6, or any of the equivalents thereof. In the locking operation, the flat face of the club tooth of the escapement wheel makes tangential contact with the curved face of the pallet, and, as the lever swings to unlock the escape wheel, a curved face of the pallet slides across the flat face of the tooth. The swinging movement-of the locking corner of the pallet through its normal path will necessitate a retrograde movement of the escape wheel, because that locking corner is square. This will cause an increasing resistance to unlocking in the case of the old style of pallet. With a pallet formed as I have shown it, the curved face of the pallet .does not cause any substantial retrograde movement of the escape wheel, but, on the other hand, will cause a decreasing unlocking resistance, which unlocking resistance may decrease so far that the pressure of the escape wheel tooth upon the pallet will actually assist in moving the lever to unlocked position. In doing away with the increasing unlocking resistance caused by the retrograde movement of the escape wheel during unlocking motion, I have done away with a serious cause of inaccuracies in timepiece operation.

In my form of escapement, the pallets 3 extend from the lever at right angles to the plane thereof, and, therefore, the escape wheel is not in the same plane as the lever. and its teeth may swing across the top of any portion of the lever without interference. In the standard form of escapement, the lever and escape wheelare in the same plane and the escape wheel must be made of such a size that it will not interfere with the lever. This is impossible in the case of small watches without making the escape wheel of 0 K n u a size other than the proper one. A further advantage of my form of escapement, therefore, is that the proper size of escape wheel can be used, no matter how small the escapement mechanism may be.

No matter what particular shape of crosssection of pallet is selected, it desirable that the opening in the lever be made to correspond therewith, so that the pallet will be firmly held against movement in any direction within its opening.

It is clear that the means which I have disclosed herein for positively fixing the pallets relatively to the lever, and particularly to each other and the axis of the lever, permits of no adjustment of the pallets. it is, therefore, necessary that the correct 'escapement wheel be assembled in combination with a lever of my type, because variations will occur in the escape wheels and also in the distance between the escape wheel bearing and the lever bearing in the plate in which these bearings are made. ll, therefore, propose to select the proper escape wheel in accordance with the method and by the apparatus disclosed in my copending application, Serial Number 91,958, for improvements in gaging apparatus, filed April 17, 1916.

From the foregoing description, it will be understood that my type of lever in combination with a club tooth escape wheel, when broadly and functionally considered, is the first wherein the pallets are fixedly and permanently adjusted and in which such adjustment is initially provided and insured prior to the assemblage of the pallets in the lever; that the escapement is fool-proof, in that no extraordinary skill is needed properly to assemble it, take it apart, or reassemble it, and no mistake in assembling is possible, even by careless and unintelligentworkmen, inasmuch as the pallet openings of the lever positively fix the lifting face of each pallet and thereby fix the amount of lock and drop and insure that it will be equal as regards each pallet. f he lever, with the openings for the staff, and the pallets may be produced in large quantities and with exact similarity, for they may be punched without the use of jigs or without necessitating operations by hand.

lVhile l have described and illustrated a particular form of my device, I do not in tend that I shall be limited to the specific details herein disclosed, but intend that my invention shall be defined only by the hereunto-appended claims.

What I claim as new and desire to secure by Letters Patent of the United States is the following 1. In a detached lever escapement for timepieces, an es ape wheel having teeth provided with lifting faces, a lever, an en trance and an exit pallet each having a lift ing face cooperating with the lifting face of a tooth of the escape wheel to produce thereby the required angular displacement of the lever, each of said pallets traversing the lever at right angles to the face of the lever and interlocked with said lever against displacement of their lifting faces in said lever.

52. In a detac led lever escapement, a lever, ensrance and eXit pallets carried thereby and extending at right angles to the face of said lever, said pallets each having a lifting face and a locking face, said ocking face being of curved contour, and an escape wheel having lifting faces coiiperating with the lifting faces of the pallets.

3 In a detached lever escapement, a lever, entrance and exit pallets of a definite contour, and having lifting faces, said lever having apertures extending from face to face thereof and of substantially the same contour as that of the pallets, said apertures heinc formed so as to provide yielding jaws for gripping and holding the pallets with .ir lifting faces in predetermined position.

at. In a detached lever escapement for timepieces, a lever, entrance and exit pallet-s practically identical. as to contour in untcd thereon and having lifting and locking' faces, and an escape wheel having teeth provided with lifting faces.

5. in a oetached lever escapement for time ieces, a ver, entrance and exit pallets practically identical as to contour mounted thereon and having lifting and locking faces, and escape wheel having teeth pro vided with lifting faces, said parts being so arranged that the drop to one pallet is substantially equal to that of the other.

In a detached lever escapement for timepieces, a lever, entrance and eXit pallets muctically identical as to contour mounted i and havinglifting and locking faces, and an escape wheel having teeth provided with lifting faces, said parts being so arranged that the lock of one pallet is substantially equal to that of the other.

7. in a detached lever escapement for timepieces, a lever, an escape wheel having teeth provided with lifting faces, and en trance and exit pallets carried by said lever and having; respectively a lifting face and a curved locking fare of such contour that the resistance to unlocking by both pallets decreases as said lever moves to unlock said escape wheel.

8. In a detached lever escapement for timepieces, lever, an escape wheel having teeth provided with lifting faces, and entrance and exit pallets carried by said lever and having respectively a lifting face and a curved locking face of such contour that unlocking either pallet producessubstantially no retrograde movement of said wheel.

U ah

9. In a detached lever escapement for timepieces, a lever, an escape Wheel having teeth provided with lifting faces, and entrance and exit pallets carried by said lever and having respectively a lifting face and a curved locking face, all being so arranged that the teeth of said Wheel make tangential contact With the locking faces of said pallets during engagement.

10. In a detached lever escapement for timepieces, a lever, an escape Wheel having teeth provided with lifting faces, and entrance and eXit pallets substantially identical as to contour carried by said lever and having respectively a lifting face and a curved locking face, all being so arranged that the teeth of said Wheel make tangential contact With the locking faces of said pallets during engagement.

11. In a detached lever escapement for timepieces, a lever, an escape Wheel having teeth provided With lifting faces, and entrance and exit pallets mounted on said lever and having lifting faces and a cross section comprising a portion of a circle having a diameter and a chord parallel thereto, said chord being formed by the lifting faces on the pallet. I

12. In a detached lever escapement for timepieces, a lever, an escape wheel, said lever having bifurcated branches one arm of which is rigid and the other of Which is yielding, and entrance and exit pallets having lifting and loqking faces, said pallets being positioned between said arms and each having the location of one of said faces fixed by said rigid arm.

13. In a detached lever escapement for timepieces, a lever, a pallet therefor having a lifting face and a face having a fiXed relation thereto, said lever having a part thereon in fixed relation to the axis of said lever, and means movable relatively to said part for holding said face having a fixed relation to said lifting face, against said part, With said pallet extending substantially perpendicularly to the plane of said lever.

14L. In a detached lever escapement for timepieces, a lever, a pallet therefor having a lifting face, said lever havin a part in fixed relation to the axis of sai lever, and means movable relatively to said part for holding a portion of said face immovable in contact With said part.

In testimony whereof, I have signed my name to this specification.

CHARLES E. DE LONG.

Witnesses:

C. H. KOEHLER, FORDYCE W. BROWN. 

